Chapter 36.—The Source of Evil or of Corruption of Good. 41.  After thus inquiring what evil is, and learning that it is not nature, but against nature, we must next inquire whence it is.  If Manichæus had done this, he might have escaped falling into the snare of these serious errors.  Out of time and out of order, he began with inquiring into the origin of evil, without first asking what evil was; and so his inquiry led him only to the reception of foolish fancies, of which the mind, much fed by the bodily senses, with difficulty rids itself.  Perhaps, then, some one, desiring no longer argument, but delivery from error, will ask, Whence is this corruption which we find to be the common evil of good things which are not incorruptible?  Such an inquirer will soon find the answer if he seeks for truth with great earnestness, and knocks reverently with sustained assiduity.  For while man can use words as a kind of sign for the expression of his thoughts, teaching is the work of the incorruptible Truth itself, who is the one true, the one internal Teacher.  He became ex ternal also, that He might recall us from the external to the internal; and taking on Himself the form of a servant, that He might bring down His height to the knowledge of those rising up to Him, He condescended to appear in lowliness to the low.  In His name let us ask, and through Him let us seek mercy of the Father while making this inquiry.  For to answer in a word the question, Whence is corruption? it is hence, because these natures that are capable of corruption were not begotten by God, but made by Him out of nothing; and as we already proved that those natures are good, no one can say with propriety that they were not good as made by God.  If it is said that God made them perfectly good, it must be remembered that the only perfect good is God Himself, the maker of those good things.